1. Field of Invention
The present invention relates to an automated manual transmission, and more particularly, to an automated manual transmission capable of improving a shift quality deterioration phenomenon that a vehicle is likely to be pulled back during a shift operation of the automated manual transmission and reducing a full length and a weight of the transmission by sharing a planetary gear device which is used for synchronization during the shift operation.
2. Description of Related Art
An automated manual transmission is automatically shifted by an actuator during a driving of a vehicle to be able to provide driving convenience like that of an automatic transmission and transmits power more efficiently than the automatic transmission to be able to contribute to improvement of fuel efficiency of a vehicle.
However, in case of the automated manual transmission based on a synchromesh type shift mechanism, it cannot avoid an instant that an engine does not transmit power even during the automatic shifting of a gear by the actuator and thus a torque is reduced, such that a shift quality deterioration phenomenon that a vehicle is likely to be pulled back may be caused.
To solve the above problem, a technology of installing a plurality of planetary gear devices between an engine and a shift mechanism to selectively transmit the power of an engine to the shift mechanism or an output depending on a driving state of a vehicle has been proposed.
Referring to FIG. 1, a power of an engine 1 is transmitted to a shift mechanism through an input by a first planetary gear device PG1 during driving and the power of the engine 1 is transmitted to an output by a second planetary gear device PG2 during shifting, thereby improving a shift quality due to the reduction in torque during the shifting. In this case, ring gears R1 and R2 installed in the first planetary gear device PG1 or the second planetary gear device PG2 during the driving or the shifting are selectively limited and thus sun gears S1 and S2 selectively rotate by rotation of carriers C1 and C2.
However, the above-mentioned related art uses a synchronizer based on a type of synchronizing and meshing a shift stage suitable for a driving speed during all the shift operations to implement each shift stage and thus the shift operation may be slow. Meanwhile, as the related art, Korean Patent Laid-Open Publication No. 10-2009-0132758 entitled “Power train for a hybrid electric vehicle with automated manual transmission” has been disclosed.
However, according to the above-mentioned method, two motors are separately mounted and thus the costs and weight may largely increase.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.